The Pediatric Oncology Program Project is an integrated grant covering clinical and preclinical studies in oncology and bone marrow transplantation. A major emphasis of this grant is related to therapeutic investigations with emphasis on marrow transplantation for the treatment of acute leukemia, non-Hodgkin's lymphoma, neuroblastoma, aplastic anemia, and for patients at high risk for kidney graft rejection. Children and adults will be treated in these studies. Emphasis is on total lymphoid irradiation and T-cell depletion of donor bone marrow to reduce the risk of development of graft versus host disease. Preclinical investigations form a major portion of this grant, complementing and interdigitating with the therapeutic studies. Included are investigations into the nature and function of committed hematopoietic marrow cells, platelet pathophysiology, cyclophosphamide metabolism, and adrenergic mechanisms in neuroblastoma. Studies of the etiology of childhood cancers will include evaluation of the role of DNA repair mechanisms and tumor viruses.